Gas burner control



Dec. 4, 1934. E J BRADY ET 1,983,213

GAS BURNER CONTROL Filed July 24, 1933 wfg l.; 1

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Patented Dec. 4, 1934 UNITED STATES PATENT OFFICE GAS BURNER CONTROLvania Application July 24, 1933, Serial No. 681,936

Claims.

The present invention relates to gas pilot lights. Gas burningappliances such as ranges, water heaters and the like, which areemployed for intermittent heating operations, are usually pro- 5 videdwith pilot lights intended to burn continuously to provide ignition whenthe larger flow of gas is turned on for the heating operation.

For purposes of economy, such pilots are arranged to burn with a smallflame, consuming only a small quantity of gas. For instance, withmanufactured gas, a typical pilot consumption on a gas range is about0.2 to 0.3 cubic foot per hour.

In the usual pilot arrangement, the flame .isv

phere at the pilot tip takes place at the needle valve, and to securethe small ow required the annulus around the needle is of verysmallwidth. In a typical case of a gas range pilot supplied with gas at apressure of 31/2 inches of water at the burner bar and a consumption of0.2 to 0.3 cubic foot per hour with the needle valve properly centeredthe orifice width is of the order of .00028 inch.

One of the recurring sources of trouble in gas distribution is theoutage of pilot lights due to stoppage of these needle valve orifices.4These outages cause expense to the distributing company in correctingthe trouble and are a source of danger to the consumer.

One of the principal causes of pilot valve stop'- page is the presenceof small particles of gummy or reslnous material in the gas. This isparticularly true in situations in which coal gas is distributed. Inother situations, dust is the principal cause of stoppage, while inothers the stoppage maybe causedv by both ygum and dust. In thecopending vapplications,Brady and Fulweiler 667,647, 'flledApril 24,1933,' and Perry and Brady`667,6`48, filed` April 24, 1933 aredescribed`improved pilot controls in which the flow of gas "to the pilotcontrolledbyQflow through a long tortuous passage the width and depth of`which is many times greater th'arrthe width ofthe usual needle ivalveorifice when adjusted for the same` A flow underthe same pressureconditions, and in reduced. z n "l 1 The principal. objecty of th.presentV invention is to" provide an improved' pilot control having sucha' long `tortuous Vpassage lfor controlling the,n

gasil'ov/"andv having` ineansforfregulating the `outer portion of theannular spring disc 13, the

Awhich the likelihood of istopliageis very greatlyy flow by changing thecross sectional areaof the passage.

Inasmuch as the flow through such a long passage varies approximately asthe fourth power of the diameter of a circle having an area equivalentto the cross sectional area of the passage, small changes in the crosssectional area of the passage produce large changes' in the flow, andthe required movement for adjustment may be very small. 4

Fig. 1 shows a cross section of one form of the invention chosen forillustration.

Fig. 2 shows a cross section of a second form of the invention.

Fig. 3 shows an end elevation of a portion of 70 the apparatus of Fig.2.

Fig. 4 shows an end elevation of an other portion of the apparatus ofFig. 2.

Fig. 5 shows in cross section a third form of the apparatus of theinvention, and

Fig. 6 is a view drawn to a reduced scale and showing the spiral gasway.

Referring to Fig. 1, 1 indicates a stationary member provided with astraight walled spiral groove, the base of which is indicated at 2. 3

`is a movable member provided with a straight walled spiral groove thebase of which is indicated at 4. The two grooves are so formed that theprojections between turns of one groove accurately t into the turns ofthe other groove and are slidable therein, forming two spiral passages 5and 6, the depth of which may be simultaneously varied by moving themovable member 4 so that the projections between the turns of groove 2extend to a greater or lesser extent into the groove 4 and theprojections between the turns of groove 4 likewise extend to a greateror lesser extent into groove 2.

The member 1 is provided with the gas inlet passage 7, threaded at 8 forthe pipe leading to 96 the gas supply, and with the gas outlet passage 9threaded at 10 for `the pipe leading to thepilot burner".` The member 1is threaded at 11 to'en-` gage the cover 12, which is screwed down onthe inner portion of which yis attached to the movable member 3,providing va gastight closure.A while permitting movement of member'3with` `respect to member 1. l The stem 14 attached to the member' 3passes through the opening 15in' the cover and isthreaded at 16 toengage the nut 17. The spring 1.8 is arranged to hold the'nut 1v againstthe over 12.*" The fmemberwsris cut. out at 19 to provide a passagebetween the' two vspiral passages formed bythe grooves, and the V squirements.

member 1 is drilled at 20 to provide a connection between the outletpassage 9 and the spiral passage 6. In operation, gas passes from thesource of supply as for instance the burner bar of a gas range, throughthe inlet passage -8 to the spiralpassage 5 and thence inwardly throughthat passage to the passage 19, from whence it flows into the spiralpassage 6 and outwardly through that passage to the connecting passage20 leading to the gas outlet 9, and thence tothe pilot burner. If the owthrough the spiral passages is decreased due,.for instance, to a drop inpressure of the gas supply, and it is desired to increase the flow, byturning the'nut 17 the member 3 is moved upwardly' with respect tomember 1 and the cross sectional area of the spiral grooves 5 and 6increased, increasing the flow of gas therethrough. As the flow variesapproximately as the square of the cross sectional area of an equivalentcircle, a slight relative movement of the two members produces arelatively large variation in flow.

If it is desired to decrease the flow, the nut 17 is moved in theopposite direction and due to a'ctionof the spring 18, the member 3 ismoved downwardly decreasing the cross sectional area of the spiralgrooves and .decreasing the ow. The spring member 13 which may be ofphosphor bronze seals off the gas from the space between the member 3and the cover 12, so that the open-I ing 15 need not be gas tight. Thespring 18 is provided with sucient spring laction to overcome theresistance of the spring disc 13. The grooves in members 1 and 3 havebeen described as spirals, other forms of sinuous or tortuous groovesmay be employed.` The arrangement of Fig. 1 lends itself to employmentwith a variety of gas appliances as a wide variation in gas ovv may besecured by adjusting the relative positions of members 1 and 3.l Withslight modification, it may be employed for controlling the ow to theburner of a gas refrigerator which burns continuously with a relativelysmall flame, but at varying rates as demanded 'by the cooling re- Forinstance, instead of providing the hand adjustment means consisting ofthe nut 17 and the thread 16, the stem 14 may be actuated bythermostatic means responsive to the cooling requirements and thegas'flow to the burner varied automatically thereby as required.

Referring to Figs. 2, 3 and 4, 30 indicates a cylindrical or slightlytapering member provided with the screw thread indicated as 31, andsurrounded by the member 32 provided with the Y. female screw thread 33.The two threads are of the same pitch: which is considerably greaterthan the combined width ofthe two threads 31 and 33, so that when thethreads are in contact at the rightof thread 31 as sho-wn, a helicalpassage 35 is provided, which at one end of the member 1 is incommunication with the gas inlet passage 36 leading fromthepip'e 37 andfrom the gas supply. The other end of the passage 35 leads through aport 38 formed in the base of the cap 39, and thence through outletpassage 40 in the member 32 to the pipe (not shown) leading to the pilotburner. The cap 39 and the member 32 may be provided with the dowel pins41 to secure proper registry of the port 38. Within a recess in themember 30 is arranged the member 42 secured to the member 30 by dowelpins 43 and 44, which permit a slight axial movement between the members30 and 42, but prevent relative rotational movement. v v

The pin 45 extends through the members 30 and 42 and is threaded at 46,engaging a threaded bore in the cap 39. A thin soft annular gasket 47 isarranged between the at surface of the member 42 and the end of themember 30. At its periphery the member 42 seats in a tapered seat formedin the member 32 and indicated at 48. The spring 49 arranged within arecess in member 42 engages the base of the recess and the head of thestem 457 which is provided with a slot for use in screwing the stem intothe cap 39. The member 42 is provided with the slot 5l for turning themember 42 and the member 30 with respect tothe member 32.

The stern 45 holds the cap tightly against the ends of the members 30and 32 and also through the action of the spring 49 holds the member 42tightly in the tapered seat 48. The gasket 47 permits a slight axialmovement between the members 30 and 42. If the various members were madewith extreme accuracy, the members 42 and 30 might be combined in onepiece, but otherwise it would be diicult to secure accurate seating ofthe end of member-30 against the cap 39, while the cap was seatedtightly against the end of the member 32 and at the same time secure atight seating of the tapered faces at 48. The provision of the separatemembers 30 and 42 with the spring and the gasket provides a littleleeway and permits the gas tight assembly of the parts without thenecessity of extreme accuracy in manufacture. In the illustration, theport 38 in the cap 39 is arranged to extend in an arc of about 120.

In operation gas ows from the inlet pipe 37 through the inlet passage 36and thence through the spiral passage 35 to the port 38, and thencethrough the outlet passage 40 to the pilot burner (not shown). In Fig. 2the spiral passage 35 is shown fully open, with the threads 31 and 33 incontact on the right side of thread 31. When a smaller ow of gas isdesired, the member 30 is turned a part of a turn by means of the slot51 in the member 42, the turning movement moves the screw thread 31 tothe left within the groove of the thread 33, narrowing the passage 35land decreasing the flow through to the pilot burner. The thread l33cooperating with the abutting surface of the thread 31 produces thisresult. The movement 0f the thread 3l to the left opens up anotherspiral passage similar to 35, but on the right of thread 31. Another wayto describe this is to say that the thread 46 plays no part in therelative turning movement of parts 30 and 32, and that a part turn ofone threaded member changes the width of the crack or space 35. Thespiral space between the turns of the thread on either member is widerthan the width of the thread on the other member, and by turningmovement, the thread of one element is moved realtive to the thread ofthe other element across the spiral space for a limited distance ineither direction. The turning movement is limited by the width of thespiral space 35. The spiral space on one member into which the spiralthread on the other member projects is wider than that. thread so thatwithout relative endwise movement of themembers. one member can beturned relative tothe other for a limited distance in one direction orthe other until the thread binds against one or the other of the wallsof the spiral spaces which are the sides of the .thread on the othermember, and between those limits a spiral passage may be provided oneither side of the thread of varying widths depending upon the relativeangular position of the two members. The slot 38 is so arranged that oneof these passages is always in communication with it and this passage isemployed as the gas control passage. The spiral passage on the otherside of the thread is always closed by the flat surface of the cap 39'.The arrangementl of the port 38 in cap 39 is such, however, that the endof this second spiral passage is blocked off by the fiat surface of thecap in all positions between the full open position of passage 35,illustrated in Fig. 2, and its fully closed position when the left sideof the thread 31 is in contact with the thread 33 and the flow of gas isthrough the passage 35 which discharges to the port 38 in all degrees ofopening of the passage 35. In the. apparatus illustrated, a rotation ofthe member 30 through 120 effects an adjustment of from 100% to 0% inthe cross section of the passage 35.

Referring to Fig. 5, indicates a spirally'coiled rod between two atgaskets 61 and 62 which may be made of resilient material such asarubber which is not materially affected by the gas and does not take apermanent set. The gaskets and rod coil are held between the twoelements 63 and 64 which are held tightly together by suitable meanssuch as the union element 65 which engages the threaded periphery ofelement 63. 66 indicates a gas inlet passage which communicates throughthe port 67 with the outer end of the spiral passage 68 which is formedby the wire coil' and the gaskets. The inner end of this passagecommunicates with the port 69 leading to the outlet passage '10. Theelement 63 may be provided with a threaded lug '71, which may be screwedinto the pipe (not shown) leading from the gas supply. The element 64may be provided with the female thread 72 into which may be screwed thepipe (not shown) leading to the pilot burner (not shown) In operationgas passes from the gas supply, through passage 66, port 67 to thespiral passage 68, through the spiral passage and thence through theport 69 and passage to the pilot burner. The flow may be decreased bydecreasing the cross section of the passage 68 by tightening the unionmember 65 and compressing the gaskets 61 and 62 into the spaces betweenturns of the wire coil 60 which form the passage.- Release of thepressure by loosening the union member 65 permits the gaskets because oftheir resiliency to withdraw from the space between the rod turns andincreases the cross sectional area of the passage 68 increasing the gasow. Pressure on the gaskets crowds parts of them into the spaces 68between the turns of the part 60 as shown in Fig. 5, and upon release ofthatpressure the gaskets resume their normally flat surfaces. Instead ofproviding the gaskets 61 and 62 of resilient material if desired theymay be provided of deformable but nonresilient material such as lead. Ins uch case, the control may be adjusted for decrease of flow bycompressing the gasket into the passage 68 and if an increase in flow islater desired, the deformed gaskets may be replaced with new ones.

Other expediente may be employed for adjusting the gas iiow through along capillary passage by varying the cross section of the passage t-hanthose illustrated. The apparatus of the invention may be employed inconjunction with either the torch or ash back methods of burner ignitionand appliances providing a readily adjustable pilot light which is notliable to outage through stoppage of the gas flow control apparatus.

It will be obvious to those skilled in the art to which the inventionrelates 4that modifications may be made in details of construction andarrangement and matters of mere form without departing from the spiritof the invention which is not limited to such matters, or otherwise thanthe prior art and the appended claims may require.

We claim:

1. A flow restricter for a gas burner comprising, the combination ofelementsA relatively adjustable in respect to each other and havingbetween them a circuitous gas way defined by walls movable in respect toeach other to increase and decrease the cross-sectional area of thecircuitous gas way when said elements are adjusted, a gas inlet at oneend of the circuitous gas way, and a gas off take at the other end ofthe circuitous gas way.

2. A flow restricter for a gas burner comprising, the combination ofelements relatively adjustable in respect to each other and havingbetween them a spiral gas way defined by intertting and overlappingspiral walls, relatively movable in the direction of their height toincrease and decrease the cross sectional area of the spiral gas waywhen said elements are adjusted, a gas inlet at one end of the gas way,and a gas outlet at the other end of the gas way.

3. A ow restricter for a gas burner comprising, the combination ofelements relatively adjustable in respect to each other and havingbetween them a spiral gas way defined by spiral walls movable faciallytowards and away from each other to increase and 'diminish the crosssectional area of the spiral gas way when said elements are adjusted, agas inlet at one end of the gas way, and a gas outlet at the other endof the gas way. Y

ALA ow restricter for a gas burner comprising, the combination ofelements relatively adjustable in respect to each other and havingbetween them a spiral gas way dened vby a spiral upon a wide variety ofgasI wall and by resilient gaskets into which the wall are adjusted, agas inlet at one end of the gas way, and a gas outlet at the other endof the gas way.

5. A flow restricter for a gas burner comprising in combination nestedelements mounted for relative rotation and each provided with a thread,and the spiral space between the thread' on one element exceeding inwidth the width of the thread on the other element, thereby providingfor two spiral passages one on each side of the thread and of which thecross sections are variable by relative turning movement of theelements, and means for causing gas to flow through and out of one ofsaid passages only.

